Bikes in the Jing
The best way to get around in the Jing is by bike. Taxis can be convenient (depending on traffic) but what you see is either going by too quickly or you are behind the window. Walking you are up close to things but it can be a bit slow. I love the subway and that has it’s own unique appeal, but you are mostly underground.
Bikes are best though because you can get around at a nice clip but you are more immersed in the city, especially as you ride along side residents just going about their business on bike. I think the next person who visits me here in Beijing, I am going to make them go on a bike ride. It’s the best way to experience the city.
Having said that, not riding your bike and just resting by it as the world goes by is also a fine option.
Tanzania Days 
That really sounds like fun. I would love to tour the city by bike, something we didn’t do when there.